Heretofore, it has been common practice to transport newly manufactured vehicles, such as automobiles, vans, and trucks, long distances on auto rack equipped railroad cars, known in the industry as auto rack cars. The typical auto rack car is compartmented, having two or more levels for storing vehicles, opposed side walls, doors in front and back or at each end, and a roof. When in transit, the vehicles are secured in place on the floor on each level of the car to prevent damage which would result from the free movement of the vehicles in the car. Various wheel or tire chocking systems exist for securing the vehicles in place on the floor. The lower floor is constructed of steel plate and coated with a suitable paint, such as a non-skid paint, while the upper floors or decks are usually constructed of galvanized corrugated steel plate.
One system for securing the vehicles in place in double-deck auto rack cars for generally transporting sport utility vehicles, which has been approved by the AAR, and which is currently in use in a large number of cars, is shown in U.S. Pat. No. 5,302,063. This system includes the placement of two spaced-apart substantially parallel rows of steel rod grating extending along the entire length of the floor or upper deck plates on each level of the car. The grating is hingedly connected to the floor, and the tires of the vehicles are positioned on the grating and chocks are adjustably connected to the grating adjacent the tires to prevent the vehicles from moving while in transit. The grating is divided into elongated rectangular ten-foot sections formed of upper and lower crossing circular steel rods interconnected by welding. The lower rods are somewhat undulated to generally mate with the upper bars, thereby defining a large number of contact points (over one thousand) that engage the floor when the grating is laying on the floor. Each grating section is pivotally attached along its entire length to the floor by suitable hinge means at one side and has a free end along its entire length at the other side opposite the hinge means. The bottom and free end of each grating section rests on the floor. The grating sections pivot upwardly about the hinged end to facilitate clearing debris, snow, ice, and other materials which accumulate under the grating.
During transit of the vehicles in the auto rack cars, the grating is loaded and the weight of the vehicles positioned on the grating holds the grating down against the floor and generally prevents movement or vibration of the grating. However, when the auto rack car is empty, the grating is not held down and the movement of the train causes continuous vibration and movement of the grating over the floor. The vibration of the grating sections against the floor at the various contact points will wear away the non-skid paint on the floor or deck or the galvanized coating of the steel corrugated plates and expose the metal surface at those contact points. The exposed metal surfaces are subject to rusting, which is highly disadvantageous in auto rack cars because rusting combined with the contact points of the grating rubbing against the points frees rust particles that become airborne when transporting cars and which can come to rest on and cause damage to the finishes of the vehicles.
In present installations, each car includes fourteen grating sections per deck. Since each grating section has over one thousand floor contact points, there would be over fourteen thousand contact points per deck. Accordingly, there is a need for a device which reduces the wear on the floor caused by the movement and vibration of the grating and thereby reduces rusting at the multitude of contact points where the grating engages the floors of the auto rack cars and thereby minimize, if not eliminate, airborne rust particles.